Hope electric



(No Model.) 2 Sheets-Sheet l' A. WRIGHT.

MAST ARM. No. 481,381. Patented Aug. 23, 1892.

(N0 Model.)

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2 Sheets-Sheet 2l A. WRIGHT. MAST ARM,

P zanxl INIZENJ'DE.'

UNITED STATES PATENT OFFICE.

AUGUSTUS VRIGl-IT, OF PROVIDENCE, RHODE ISLAND, ASSIGNOR TO THE HOPEELECTRIC APPLIANCE COMPANY, OF SAME PLACE.

MAST-ARM.

SPECIFICATION forming part of Letters Patent No. 481,381, dated August23, 1892.

Application jtiled October 14, 1891. Serial No. 408,693. (No model.)

To au whom t may concern.:

Be it known that I, AUGUSTUS WRIGHT, of the city of Providence, in thecounty of Providence and State of Rhode Island, have invented certainnew and useful Improvements in Mast-Arms; and I hereby declare that thefollowing is a full, clear, and exact description of the saine,reference being had to the accompanying drawings, forming part of thisspecification.

This invention has reference to improvements in mast-arms ordinarilyused to support electric lamps.

The object ot the invention is to produce a mast-arm having greatstrength and rigidity, while the Weight of the same is greatly reduced.

A further object of this invention is to provide a mast-arm with atrolley rail or wire, along which the lamp-support is adapted to move,and mechanism automatically operated by the movement of the lampcarriage or support to cut the lamp into or out of the electric circuitand to close said circuit when the lamp is thus cut out.

The invention consists in the peculiar construction and novelarrangement of the stays forming the arm, together with the bridge orbrace connecting the stays.

The invention also consists in the combination, with thispeculiarly-constructed mastarm, of an automatic switch andcircuit-closing device adapted to be operated by the lamp carriage orsupport, as will be more fully described hereinafter, and pointed out inthe claims.

Figure 1 represents a view of a portion of a mast, to the upper portionof which the improved mast-arm is shown as secured and indicating themethod of moving the lamp from one end of the arm to the other. Fig. 2represents an enlarged top view of the outer end of the arm, partly insection, showing the automatic switch and circuit-closing device and thecircuits connecting therewith. Fig. 3 represents an enlarged top View otthe cross-arm with the butt-ends of the side-stay tubes secured theretoand showing the bolts by which this cross-arm is secured to the mast.Fig. 4 represents an enlarged view of the outer end of the mast-arm,partly in section, to more clearly show the construction and to indicatethe operation of the circuit-breaking device.

Similar numbers of reference designate corresponding parts throughout.

As mast-arms for supporting electric lamps are supported on masts atconsiderable distances from the ground and are subjected to greatstrains from the pressure of the wind in addition to the weight of thelamp, it has been found that these arms should be of great rigidity, butof extreme lightness. The flexible cables connecting the lamps with themain circuits, as heretofore constructed, owing to the constant wearfrom the movement ot the lamp or `from rubbing against the metal Work ofthe arm, are a source ot expense and continual source of danger to theoperatives when handling the lamps. In order to produce an arm having'great resisting power from pressure exerted in any direction and toavoid the elements of danger to which operatives have heretofore beenliable, I have invented the mast-arm and switching devices which I shallnow more particularly describe.

In the drawings, 5 indicates the mast on which the arm is secured andsupported. The arm is formed by the side-stay tubes 6 and 7, secured attheir inner or butt ends to the cross-arm S, which is provided withbolts, by which it is fastened to the mast 5. The sidestays tubes 6 and7extend outward and downward at angles with the cross-arms 8, approachingeach other, and are connected at their outer ends by the bentpipe-t-tingtl, having a block 10 secured thereto. The upper stay-rod 1land the trolley-stay 12 are secured at their outer ends to the block 10,the stay-rod 11 extending upward and its inner end being secured to themast 5 bythe adjustable eyebolt 13, while the trolley-stay 12 is alsosecured to the mast 5 by the adjustable eyebolt 14 at a point on themast practically on a level with the outer end of the mast-arm. Theupper stay-rod 11 and the side-stay tubes 6 and 7 are also braced andconnected by the bridge 15 through perforations in which they extend.

Inclosed within and secured to the bend of the pipe 9 is a block 1t', inwhich a grooved pulley 17 is movable on a shaft, while on the mast 5 andimmediately below the cross-arm 8 is secured a bracket 18, in which thegrooved IOO pulley 19, operated by the crank 20, is journaled. Overthese grooved pulleys 17 and 19 is stretched the endless rope or band21, secured to the upper portion of the lamp-carriage 22, which isprovided with a trolleywheel adapted to travel on the trolley-stay 12when moved by the rope or band 21. The forward end of the lamp-carriageis also provided with the bent arm 23, while the sides of this carriageare provided with the contact-plates 24 24, pro perlyinsulated therefromand connected with opposite poles ot the lamp.

Near the outer ends of the side-stay tubes (i and 7 are secured theinsulating-blocks 25 and 26, carrying spring contact-plates, which areconnected with the main circuit by conductors extending through thetubular side stays. The conductor extending through the tubular stay 6is continued through the bent pipe-fitting 9 and is connected with onepost of a spring-closed switch, the other post of which is connectedwith the conductor in the stay-tube 7. This switch has a contact-arm 27,pivotally secured to the metallic blocks 27', carried by but insulated.from the staytube 7 and connected with one end of the electricconductor, while connected with the other end of the electric conductoris a contact-plate 28, also carried by the stay-tube 7 and insulatedtherefrom, the contact-arm 27 being adapted to electrically connect theblocks 27 and 2S together.

Formed in part with the contact-arm 27 is an operatingarm 29, extendingat an angle with said contact-arm and operated by the spring 29 to keepthe free end of the contact-arm in electrical contact with the plate 28,except when sufficient pressure is exerted against the arm 29 to throwthe same backward and move the free end ot' the contact* arm 27 awayfrom the plate 2S. As the lampcarriage 22 is moved outward by the ropeor band 21 the contact-plates 24 24 will be forced in between thespring-plates carried by the blocks 25 and 2G and a split circuit willbe established through the lamp. The carriage 22 being moved stillfarther outward will cause the bent arm 23 to strike the operating-arm29 of the switch and force this arm backward, which will move the freeend of the contact-arm 27 away from the plate 2S, breaking theconnection between the ends of the conductor, and thus throwing thewhole strength of the electric circuit through the lamp.

When it becomes necessary to vtrim the lamp, the crank 20 is turnedbackward, imparting motion to the carriage 22 through the rope 21 tomove the carriage toward the mast. Asthe pressure of the bent arm 23 isremoved from the spring-operated arm of the switch, this arm will beoperated by the spring and the switch closed, splitting the circuit. Themovement ofY the carriage destroys the connection between thecontact-plates on the carriage and those secured to the blocks 25 and26. The lamp may now be trimmed by the operative without danger fromreceiving an electric shock, while the circuit is not broken by theremoval of the lamp.

In securing the mast-arm in place the crossarm S is first secured to themast at a proper height. The upper stay-rod 11 is now adjusted by theeyebolt 13 to support the outer ends of the side stays practically on alevel with the inner ends of the same. The trolley-stay is now tightenedto bring the upper and side stays into the position shown in Fig. 1 ofthe drawings.

The outer end of the mastearln and the switches may be protected fromthe weather by the hood 30, it desired.

Having thus described my invention, I claim as new and desire to secureby Letters Patent- 1. In a mast-arm, the combination, with a tubularframe formed by the fitting 9 and the side stays 6 and 7 and a cross-armS, se-

cured to the butt-ends ot said stays, of an upper stay 11, secured tothe outer end of said frame and supporting the same, a tensiontrolleystay 12 for depressing the outer end of the mast-arm, adapted to supporta lamp-carriage, and means for operating said carriage,

as described.

2. In a 1nastar1n, the combination, with a tubular frame formed by thefitting 9 and the side stays 6 and 7, a cr0ss-ar1n 8, secured to thebutt-ends of said stays, an upper stay l1, secured to the outer end ofsaid frame and supporting the same, and a trolley-stay 12, carrying thelamp support or carriage 22, and means for operating said carriage, of aswitch secured to the outer end of said tubular frame, adapted to beoperated by said earriage to cut the lamp into and out of circuit, asdescribed.

3. In a mast-arm, the combination, with a tubular frame formed by thetubular stays (3 and 7 and the fitting 9, suitably supported andcontaining electric conductors, the insulating-blocks 25 and 2G, securedto said stays and provided with spring contact-plates connected withsaid conductors, and a spring-operated circuit-closing device alsoconnected with said conductors, of a lamp-carriage 22, moving on atrolley-stay 12 and provided with the contact-plates 24 24, connectedwith 0pposite poles of the lamp, and a forwardly-ex- IOO IIO

tending bent arm 23, adapted to operate said circuit-closing device, asdescribed.

AUGUSTUS WRGIIT. Witnesses:

JOSEPH A. MILLER, Jr., HENRY J. MILLER.

